1. Field of the Invention
The invention relates to an electrostatic coating apparatus and an electric conductivity check method therein, and for example, relates to an electrostatic coating apparatus that requires the confirmation of the electric conductivity of a coated matter after the coated matter is coated with electrically conductive primer, and an electric conductivity check method therein.
2. Description of Related Art
As a method for performing the coating of a coated matter, there is an electrostatic coating. In the electrostatic coating, a high voltage is applied to a coating gun or the like, and an electric field is generated between the coating gun and the coated matter. Then, in the electrostatic coating, a coating material electrified by the high voltage is sprayed from the coating gun to the coated matter, and thereby, the coating of the coated matter is performed. On this occasion, in the case where the coated matter is a component with a low electric conductivity such as a resin component, electrically conductive primer is applied on a coated surface of the coated matter, and after the electric conductivity is secured, the electrostatic coating is performed. In the case where the electrically conductive primer is applied on the coated matter in advance in this way, it is necessary to confirm that the electric conductivity is secured, after the electrically conductive primer is applied. The confirmation of the electric conductivity is performed by confirming whether the coated matter is earthed. Hence, Japanese Patent Application Publication No. 2012-071224 discloses an exemplary technology for confirming the earth state of the coated matter.
An electrostatic coating apparatus described in JP 2012-071224 A includes a coating gun that sprays a coating material to a coated matter, a robot arm that supports the coating gun such that the coating gun can be displaced, a high-voltage generation apparatus that generates a high voltage to be applied to the coating gun and that regulates the generated high voltage by detecting the discharge current generated between the coating gun and the coated matter. Then, the electrostatic coating apparatus in JP 2012-071224 A electrifies the coated matter with electric charge by forming an electric filed from the coating gun toward the coated matter, when the coating gun does not spray the coating material toward the coated matter, and detects the discharge current generated between the coating gun and the coated matter, by the electric charge of the electrified coated matter, when the high-voltage generation apparatus does not apply the high voltage to the coating gun.
However, in the technology described in JP 2012-071224 A, it is necessary to provide a process for confirming the earth state, separately from the electrostatic coating process. That is, in the technology described in JP 2012-071224 A, the coating process includes the process for confirming the earth state, causing a problem in that the total time for the coating process is long.